Abstract

Background

To describe the epidemiology and possible risk factors for the development of multidrug-resistant
tuberculosis (MDR-TB) in Namibia.

Methods

Using medical records and patient questionnaires, we conducted a case-control study
among patients diagnosed with TB between January 2007 and March 2009. Cases were defined
as patients with laboratory-confirmed MDR-TB; controls had laboratory-confirmed drug-susceptible
TB or were being treated with WHO Category I or Category II treatment regimens.

Results

We enrolled 117 MDR-TB cases and 251 TB controls, of which 100% and 2% were laboratory-confirmed,
respectively. Among cases, 97% (113/117) had been treated for TB before the current
episode compared with 46% (115/251) of controls (odds ratio [OR] 28.7, 95% confidence
interval [CI] 10.3–80.5). Cases were significantly more likely to have been previously
hospitalized (OR 1.9, 95% CI 1.1–3.5) and to have had a household member with MDR-TB
(OR 5.1, 95% CI 2.1–12.5). These associations remained significant when separately
controlled for being currently hospitalized or HIV-infection.

Conclusions

MDR-TB was associated with previous treatment for TB, previous hospitalization, and
having had a household member with MDR-TB, suggesting that TB control practices have
been inadequate. Strengthening basic TB control practices, including expanding laboratory
confirmation, directly observed therapy, and infection control, are critical to the
prevention of MDR-TB.